Background:

Vulval cancer causes 3–5% of all gynaecological malignancies and requires surgical removal and inguinofemoral lymphadenectomy (IFL). Complications affect > 50% of patients, including groin wound infection, lymphoedema and cellulitis. A sentinel lymph node (SLN) is the first groin node with the highest probability of malignancy. SLN biopsy would be useful if it could accurately identify patients in whom cancer has spread to the groin, without removing all groin nodes. SLNs can be identified by isosulfan blue dye and/or technetium-99 (^99mTc) radioactive tracer during lymphoscintigraphy. The blue dye/^99mTc procedure only detects SLN, not metastases – this requires histological examination, which can include ultrastaging and staining with conventional haematoxylin and eosin (H&E) or immunohistochemistry.

Objectives:

To determine the test accuracy and cost-effectiveness of the SLN biopsy with ^99mTc and/or blue dye compared with IFL or clinical follow-up for test negatives in vulval cancer, through systematic reviews and economic evaluation.

Data sources:

Standard medical databases, including MEDLINE, EMBASE, Science Citation Index and The Cochrane Library, medical search gateways, reference lists of review articles and included studies were searched to January 2011.

Methods:

For accuracy and effectiveness, standard methods were used and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were to January 2011, with no language restrictions. Meta-analyses were carried out with Meta-Disc version 1.4 (Javier Zamora, Madrid, Spain) for accuracy; none was appropriate for effectiveness. The economic evaluation from a NHS perspective used a decision-tree model in DATA TreeAge Pro Healthcare 2001 (TreeAge Software, Inc., Williamstown, MA, USA). Six options (blue dye with H&E, blue dye with ultrastaging, ^99mTc with H&E, ^99mTc with ultrastaging, blue dye/^99mTc with H&E, blue dye/^99mTc with ultrastaging) were compared with IFL. Deterministic and probabilistic sensitivity analyses were conducted.

Results:

For accuracy, of the 26 included studies, most evaluated ^99mTc/blue dye combined. Four studies had clinical follow-up only for test negatives and five had clinical follow-up for all and IFL for test negatives. Numbers with no SLN found were difficult to distinguish from those with negative SLN biopsies. The largest group of 11 studies using ^99mTc/blue dye, ultrastaging and immunohistochemistry had a pooled sensitivity of 95.6% [95% confidence interval (CI) 91.5% to 98.1%] and a specificity of 100% (95% CI 99.0% to 100%). Mean SLN detection rates were 94.6% for ^99mTc, 68.7% for blue dye and 97.7% for both. One study measured global health status quality of life (QoL) and found no difference between SLN biopsy and IFL. One patient preference evaluation showed that 66% preferred IFL rather than a 5% false-negative rate from SLN biopsy. For effectiveness, of 14,038 references, one randomised controlled trial, three case–control studies and 13 case series were found. Approximately 50% died from vulval cancer and 50% from other causes during follow-ups. Recurrences were in the ratio of approximately 4 : 2 : 1 vulval, groin and distant, with more recurrences in node-positive patients. No studies reported QoL. For cost per death averted, IFL was less costly and more effective than strategies using SLN biopsy. For morbidity-free survival and long-term morbidity-free survival, ^99mTc with ultrastaging was most cost-effective. Strategies with blue dye only and H&E only were never cost-effective. The incremental cost-effectiveness ratio for ^99mTc with ultrastaging compared with IFL was £4300 per case of morbidity-free survival and £7100 per long-term morbidity-free survival.

Limitations:

The main limitations of this study include the lack of good-quality evidence on accuracy, effectiveness and QoL. A large project such as this takes time to publish, so the most recent studies are not included.

Conclusions:

A sensitive and specific combined metastatic SLN detection test and information on generic QoL in vulval cancer is urgently required.

Funding:

The National Institute for Health Research Health Technology Assessment programme.

Article history

The research reported in this issue of the journal was funded by the HTA programme as project number 09/112/03. The contractual start date was in November 2010. The draft report began editorial review in April 2012 and was accepted for publication in May 2013. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors' report and would like to thank the reviewers for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.